From last few days, i am noticing the posting of spam threads (for e.g., the recent ones like Louis Vuitton Bags, North face outlet, http://www.chanelbagstome.com) I simply don't know what all this? If it is really a spam how we can avoid it? and if not then please correct me.

Yes, those are spam messages. We, like many other web forum sites, have to balance security with user experience. Having security too restrictive and time-consuming may persuade people not to post, while no security increases the spam. We do employ a captcha test when people register for this site, which should block most spam programs. However, this doesn't prevent human spammers from signing up and then running scripts to post a lot of threads. We have considered a probationary period for new users to cut down on the spam, but this ultimately hurts new users who might want to post/reply right away.

For now, please report any spam you see. We try to do a good job and clean them up daily.